Floor underlayment



FIG. 1 is a perspective view of a floor underlayment in accordance with the present invention;

FIG. 2 is a top plan view of the invention illustrated in FIG. 1;

FIG. 3 is a side elevational view of the invention illustrated in FIG. 1; and,

FIG. 4 is a bottom plan view of the invention illustrated in FIG. 1. 

CLAIM The ornamental design for a floor underlayment, as shown and described. 